Download - SEPARATION METHODS
Methods of Separating
Mixtures
What is a mixture?
When two or more materials or
substances are mixed together
but do not chemically
combine.
This means they retain their
original properties.
This means they can be
separated by physical means.
What are the different ways of
separating mixtures?
1. Magnetism
2. Filtration
3. Centrifuging
4. Decanting
5. Extraction and evaporation
6. Chromatography
7. Distillation
8. Crystallization
1- MAGNETISM
If one component of the mixture has magnetic
properties, you could use a magnet to separate
the mixture. Iron, nickel, and cobalt are all
materials that are magnetic.
Not all metals are magnetic: gold, silver, and
aluminum are examples of metals that are not
magnetic.
Magnetism examples
2- FILTRATION
Used when separating a solid substance from a fluid
(a liquid or a gas) by passing a mixture through a
porous material such as a type of filter.
Works by letting the fluid pass through but not the
solid.
Examples of filters: coffee filter, cloth, oil filter, even
sand!
Filtration is used to separate an insoluble solid from a
liquid.
Insoluble solid
trapped in
filter paper
Funnel with
filter paper
2- FILTRATION
Mixture of
solid and
liquidStirring
rod
Filtrate (liquid
component
of the mixture)
Filter paper
traps solid
Funnel
Filtration examplesUsing a coffee filter to separate
the coffee flavor from the coffee
beans.
Spin sample very rapidly:
denser materials go to
bottom (outside)
To use this method,
materials need to have
different density
Example: Separate blood
into serum and plasma
◦ Serum (clear)
◦ Plasma (contains red blood
cells ‘RBCs’)
Check for anemia (lack of iron)
Blood
RBC’s
Serum
A B C
AFTER
Before
3- CENTRIFUGING
Centrifugation examples
Go to the video
Go to the animation
4- DECANTING
Immiscible liquids, such as oil and water can
be separated by using a separating funnel.
The mixture is put into a separating funnel,
shaken and allowed to settle.
The oil and water from two separate layer. The
liquid with higher density, in this case water
forms the lower layer.
Remove the stopper and open the tap after
standing. The water runs out through the tap.
The oil remains in the funnel and can be run out
into another beaker
Decanting examples
Separating funnel
6- CHROMATOGRAPHY
A series of techniques used to separate a complex
mixture of substances
The mixture is dissolved in a fluid called the mobile
phase, which carries it through a structure holding
another material called the stationary phase. The various
constituents of the mixture travel at different speeds,
causing them to separate.
6- CHROMATOGRAPHY
There are many different types of chromatography methods
one of which is PAPER CHROMATOGRAPHY
This is good for separating, for example, dissolved substances
that have different colours, such as inks and plant dyes.
It works because some of the substances dissolve in the liquid
better than others, so they travel further up the paper.
Separation occurs because various components travel at
different rates on the stationary phase (chromatography paper)
Components with strongest attraction for paper travel the
slowest
6- CHROMATOGRAPHY
We often used chromatography to identify the substances
in a mixture. It is commonly used in hospitals. It helps
doctors to find out whether the patient has diabetes, if
paper chromatography might find out whether sugar is
present in the patient's urine.
Go to the video
7- DISTILLATION
This is good for separating a liquid from
a solution. Can be used to separate liquid
from liquid (alcohol from water) or solids
from liquids (water from salt)
This method works because the
substances that we are separating have
different boiling points.
For example, water can be separated from salty water by simple
distillation. Water evaporates from the solution, but is then cooled
and condensed into a separate container. The salt does not
evaporate and so it stays behind.
7- DISTILLATION
liquid with a solid
dissolved in it
thermometer
condenser
tube
distilling
flask
pure
liquid
receiving
flaskhose connected to
cold water faucet
Distillation examples
Distillation examples
Go to the video
Go to animation
Go to video 2
8- CRYSTALLIZATION
Separation technique that results in the
formation of pure solid particles from a solution
containing the dissolved substance
As the solvent evaporates, the dissolved
substance comes out of solution and collects
as crystals
Remember that it is the water (or solvent) that
evaporates away, not the solution
Produces highly pure solids
Rocky candy is an example of this